Flame and Shadows
by BrokenButterflies666
Summary: Rin dreams of blue flames every night. When the Vatican discovers her, Rin finds help from an unlikely source to escape fate and begins to turn the tides on the most ancient war of humans vs demons. Fem!Rin
1. Chapter 1: Awakening

Summary: Rin dreams of blue flames every night. When the Vatican discovers her, Rin finds help from an unlikely source to escape fate and begins to turn the tides on the most ancient war of humans vs demons. Fem!Rin

Hi guys, this is my first fanfic! Please review to help me improve. I'll try to update as frequently as I can but as I'm in college I can't promise a regular update schedule.

I do not own Ao no Exorcist or any of the characters.

* * *

 _Blue flame surrounded Rin, but it was warm and didn't burn her. The aura it emitted was almost… friendly._

" _My dear Rin, we have much to discuss."_

" _Who are you?" Rin could feel the nagging at the back of her head, like she should know who the flames represented._

" _I am _" The voice replied, the name slipping out of Rin's memory as soon as she heard it. Why couldn't she retain a simple name? With a frustrated grunt she decided to try a different question._

" _Why are you here? Why don't the flames hurt?"_

" _Why would I want to hurt you, my precious daughter? I'm here to teach and protect you."_

 _Rin couldn't shake the conflicting emotions. Her instincts were telling her to trust the flames, that they would indeed protect her. But something unsettled her still, The same tip-of-the-tongue, nagging feeling told her to be careful of the lulling voice._

" _Our time for now is over, but I will see you again soon. I promise I'll teach you all you need to know about Gehenna and demons."_

Rin awoke with a start, the dream already fading but the conversation still lingering in her mind, She was talking with someone, who? She shook her head as the answer seemed to slip further away. Looking over at the other side of the room, Rin noticed that the immaculately kept side of the room was missing it's usual occupant. Alarm blasted away any last traces of the strange dream as the dark-haired girl realized she was late for class. Again.

Quickly throwing on her school uniform and hoisting her trusty sword onto her shoulder, Rin made her way through the abandoned dormitory and began to cross the school grounds on her way to the main buildings. Despite the urgency in her step, she enjoyed the sunshine on her skin and the chirping of the mid-morning birds. Rin hated having to sit through boring 'normal' classes, but that was the requirement she had to fulfil in order to attend the cram school that would allow her to become an exorcist. That was the only reason she wasn't dead or a fugitive.

Shaking off the sudden mood shift from her thoughts Rin snuck into class without the teacher noticing she was late. She settled into her seat at the back of class and prepared for another boring day of lectures.

* * *

"Hey Shiemi!"

"Oh, hi Rin" the petite blonde responded with a smile. Ever since Rin had helped her overcome the influence of a plant demon that had made her temporarily unable to walk, they had been best friends. Attending the cram school together, both girls dreamed of becoming stronger to protect the ones they love.

The girls sat down at their seats in the front of the class and waited for their teacher to come. It was strange, getting used to her twin brother being her teacher, but somehow it felt normal now. Bon arrived with Konekomaru and Shima in tow and not too long after Yukio entered the classroom and began to teach the lesson.

* * *

" _Don't you ever act like you're my father again!" she screamed. A slap across the face snapped Rin out of her rampage._

" _We have no time for petty arguments. Just do as you're told." Shiro told her firmly._

" _Fine"_

 _Just as she was about to turn around, Shiro fell to the ground, struggling to breathe._

" _Hey old man, what's wrong?"_

" _Get away from me!" Shiro shouted, feeling Satan beginning to possess him. Maniacal laughter ushered out of his lips._

" _Dad?" came the hesitant question._

" _That's right! It's your dear old dad Satan, but you can call me papa if you'd like," more laughter followed. "Now, this body isn't going to last long so let's bring you to Gehenna where you belong." With that Satan ripped off his fingers, blood pooling at his feet and bubbling. The Gehenna gate began to form. Satan snatched Rin from where she was standing and threw her in._

" _No! Old man!"_

 _Satan just smiled._

Rin pulled herself out of her memories and tried to pay attention to the classroom she was in. Finding out that her twin brother knew about her being the daughter of Satan had hurt a lot at first, but things have settled down since then and Rin was used to seeing Yukio at the front of the class lecturing about anti-demon pharmaceuticals. Had someone told Rin a year ago this would be her life she would've laughed in their face.

"That's all for today. Class dismissed."

Rin collected her books and headed out of the classroom with a wave to the fellow exwires, her friends. It felt weird to admit she had friends after years of being bullied for protecting her younger twin.

Now in her bedroom, Rn decided to take a nap before she would work on homework. She was exhausted from having to sit still for so long. With a yawn she curled up in bed, snuggling up to her cat familiar, and drifted off to sleep.

* * *

 _Surrounded by blue flames again, Rin just looked around before shrugging._

" _Tell me what the exorcists have been teaching you so far."_

 _Rin still felt the need to be cautious of the flames but decided it would be good review to try to remember what was happening in the cram school._

" _Umm, we're learning about types of demons and something about medicinal plants I think," she scratched the back of her neck with a sheepish grin._

" _Well, let me teach you about the types of demons and you'll know more than those exorcists do."_

The dreams continued on for some time like this, the information imparted to Rin through these dreams helping her with the exorcist cram classes.

* * *

Sitting on a throne made of glistening obsidian was an ageless dark haired man. A smile played across his lips as he thought of his daughter and her progress. She was a brilliant mind when she applied herself and Satan couldn't be more proud. He hated that she chose to side with the exorcists, the betrayal hurt he'd admit, but all would work out in the end. It pained him to know that his daughter would be in danger as soon as the exorcists found out about her heritage which is why he was trying to prepare her as much as he could now. When the time came, he'd be there for her. He'd show her who the true demons were.


	2. Chapter 2: The Trial

AN: Thank you so much for all of the follows, favorites, and reviews! Also, I'd like to apologize, the beginning of this chapter is going to be right from the manga but I couldn't think of how else to get to where I needed for the plot to advance. I know I get bored of reading rewrites of the manga and I hope you'll bare with me. I promise it's all original content after this. With that said I hope you enjoy this newest chapter!

* * *

 _Of all the ways that my secret could have come out, this was by far the worst_ , Rin thought.

As part of their training, the exwires were on a camping trip. Then Amiamon had to show up and threaten her friends, forcing her to reveal her flames to everyone. As if the rejection from the exwires wasn't enough, the Paladin himself showed up and escorted Rin, Mephisto, and Shura to the Grigori trail, where Rin fate was to be decided.

"I ask everyone here, will you not take a gamble with me?" Mephisto inquired of his audience. "Will you gamble that this child of satan will become a demon king of Gehenna? Or will she become the knights, nay, will she become Assiah's savior?"

The Padalin responded angrily, "Don't let yourselves be fooled by this charlatan! Everyone, don't tell me you could have possibly forgotten his lineage! His kind specialize in smooth talking people! He conspired with Fujimoto Shiro to bring up Satan's spawn! He must have been intending to deceive the knights of the True Cross order and overthrow them from within. If you believe his words, you'll have fallen for his trick!"

Murmurs could be heard throughout the courtroom as people discussing Angel's accusations. The talking grew louder as arguments broke out, those who wanted to see Mephisto's wager through battling out those who believed the Satan spawn to be too dangerous.

Something snapped in Rin. From the beginning of the trail all she could feel was self pity for having been so stupid as to reveal her secret to the world. As the noise grew louder she felt anger. Weapon? King? She was none of these things.

"Shut the hell up!" Rin shouted, flames bursting into life around her. The audience shushed, surprised at her outburst. "I ain't your weapon, demon king, or saviour. I'm Okumura Rin! And I'm gonna become the best exorcist you ever laid eyes on! I'll make every single damn one of you remember it!"

There was some chuckling at the thought of the daughter of Satan becoming a Paladin, the most powerful rank an exorcist could claim.

"Silence everyone!" rang out a voice, the leader of the Grigori trail. "It is true that by their very nature, demons are Assiah's enemy. But then again, since ancient times, our order has gained wisdom from the demons and used that against them. That is a fact. Considering the 200 years that Sir Pheles has served the order, he holds a certain amount of trust. Everyone, will you or will you not take part in of this gamble Sir Pheles speaks of? Why don't we take a majority vote. All in favor raise your hands." Only a few hands went up. "All against." There was no contest, and with that Rin knew she was doomed. "Very well. Sir Pheles, we deem your wager too risky, and sentence the daughter of Satan to death. She will be kept in a warded cell until the time of her execution."

Mephisto looked disappointed for a second, frustrated that he plan didn't work out. A smile quickly replaced itself on his face as his brain worked out a way to turn this to his advantage.

With that, the trial adjourned and Rin was led off to the basement of the Vatican headquarters, where the prison cells were being prepared for a certain demon spawn.

* * *

The room was stunned quiet. Yukio had finished explaining about the twins' origins and how Rin was the one of inherit the demonic heritage. Bon was seething, only just barely containing his anger as Shima patted him on the shoulder. Konekomaru was shivering from fear. _Rin, the daughter of Satan?_ He couldn't believe they trusted such a dangerous person. Shiemi teared up. She couldn't believe that Rin had shouldered such a burden and didn't trust her enough to tell her. She felt useless in the face of the news. Izumo and Shima appeared to be the only ones unaffected by the news.

Just as Bon opened his mouth, their teacher Kaoru Tsubaki walked into the room.

"I'm here to inform you of the Grigori's decision on the spawn of Satan. She has been deemed a danger and is sentenced to be executed." The exorcist looked over at Yukio and felt a pang of guilt for having to bring such troubling news to the twin. "I'm sorry, Yukio."

Yukio was rooted to his chair in shock. _No! This can't be happening,_ he thought. His older sister, who he swore on his father's grave to protect, was now dead. There was nothing he could do, he wasn't strong enough to protect her. He was brought out of his thoughts by the door closing as the Kaoru let them have some privacy to grieve for their friend and sister. Shiemi's loud sniffling filled the room as she tried and failed to contain her tears. Even Bon looked shaken, his anger dissipated as the heavy weight of reality descended upon him.

* * *

 _Blue flames surrounded her again. This nightly dream was the one place of tranquility in Rin's crumbling world. The flames licked caressingly at her hands, jumping around as if unsure of how to comfort the upset girl._

" _What is the matter my dear?"_

" _The Vatican… they found out about me, about my flames. And," Rin choked, trying to hold back tears, "they're gonna kill me."_

 _The flames became unbearably hot, smothering anger whirling around. As suddenly as the anger flared it cooled again._

" _I will find a way to prevent that. Listen, my child. You will not die at the hands of those scum. I promise you that it will be alright."_

 _Rin didn't care that it was just a dream, the words soothed her nonetheless. Even though in the back of her mind she knew the world would be the same when she woke, for now she took solace in the words, hoping that somehow they would become true._

* * *

"Demons are our sworn enemies, that thing should have just been killed on the spot."

"I know, but think of all we can learn! It's not everyday that we have a high class demon to experiment on, let alone a spawn of Satan himself."

"Is it worth the risk? It can use those flames. Satan's flames."

"She's only a child, and so untrained that she couldn't hurt us if she tried."

Silence followed as the cloaked figure deliberated.

"Fine. I'll take it to the Grigori and see if we can get the execution stayed for a while. But I'm telling you, if anything goes wrong it'll be on you."

The scientist grinned, his argument won. There was still the Grigori to convince, however that was but a small matter now. He got the vote and the voice that would sway them.


	3. Chapter 3: Experimentation

AN: I'm so sorry this took forever to write and get posted. School got busy then I got a job, so I can't promise regular updates like I was hoping I'd be able to this summer. However, I will never abandon this story even if it takes me a while to write. Thank you all for sticking with me through the slow updates. I hope you enjoy this latest chapter!

* * *

Scientists garbed in long white coats came to take Rin out of her cell. She could tell something was off. She was expecting lots of exorcists in their black trenchcoats to see her off to her execution, not this.

They arrived at a large, sterile smelling medical room. Stainless steel tables lined the walls, some filled with all sorts of tools. In the middle of the room was a hospital bed with straps attached. Rin's stomach dropped. She may not be the smartest, but she could easily deduce that someone had been allowed to try a few things before her death, if these experiments didn't cost her life in the process!

"Welcome to my laboratory. I apologize for the state it is in, I had to get ready quite quickly. I am Dr. Matsumoto, and we'll be performing just a few experiments with you. I hope you will be most cooperative."

If the bad feeling was any indication before, now Rin was on the verge of panic. She tried to take a breath to calm herself.

"Now, if you don't mind let get the first experiment underway. Sit on the bed here and roll up your sleeve," the doctor continued. Rin did as she was told, not wanting to risk being forced physically. Even if she wasn't a willing participant to these experiments, she'd be damned if she let her escorts man-handle her into it.

The doctor went to the corner of the room and grabbed a needle with a pale blue substance already inside it. Coming back to Rin in the middle of the room he felt for a vein on her arm and uncapped the needle. "This may hurt a little," he warned just as he inserted the needle and injected it.

"Hey, what are you... Arhg," Rin started to protest before pain started shooting through her arm and into the rest of her body. It felt like she was on fire and drowning at the same time. Screams filled the room, and it took Rin a minute to realize those screams were hers.

"This is a power suppressing serum. Highly experimental, we've never had the chance to try it on a higher class demon before. As much data as we could get from you at full strength, it is safer for us to dampen that power just a little bit. And this serum did need to be tested after all." Rin barely heard the doctor's explanation over the ringing in her ears. The pain had subsided but only barely. She watched him writing on his clipboard as the minutes dragged on.

"That will be all for now, you can take her back to her cell," Dr. Matsumoto told the assistants. Rin stumbled as she was escorted back through the hallways, her body feeling heavy and unresponsive to her brain. Once they arrived Rin fell right onto the cot at the back of the room, too exhausted to flinch at the loudness of the door slamming behind her.

* * *

" _How dare they?" Outrage made the flames dance high and bright, matching the rage in the voice. "My poor child. You can still use your powers though they try to suppress them. Reach out with your mind and feel your flames calling to you."_

 _Rin closed her eyes, turning her attention inwards and towards the hot sensation in her gut, Her flames, she knew. "I can feel it," she told her mentor._

" _Good, now expand it. Let it take up your whole body." the voice instructed._

 _She did so, letting the sensation run through her. She was on fire, but it was more pleasant than the experiment before. This was her fire._

" _That's it. Now, whenever you need your power just call on it like that. The serum will wear off, but it cannot truly stop your powers in the meantime. Not while you're in tune with yourself."_

* * *

The weeks dragged on, each day bringing with it a new torture. Rin lost count of how long she had been kept a prisoner. She had tried to fight back on a number of occasions but found that brought on more pain, so she learned to go along with what the experimenters wanted. At least on the surface, for every night she trained with the flames, honing her skills for the chance to escape.

"We've got a new grade of holy water, but we need to see how effective it really is. I hope you won't mind helping us out with that, Okumura-chan," Dr. Matsumoto mocked, bringing Rin back to the present. Rin bit back a retort, knowing that would only make it worse for her.

And so another day proceeded. Rin was brought back to her cell at the end of it bloodied and burnt. She reached into herself and brought up her powers to start healing the burns left from the holy water before collapsing onto the cot and closing her eyes. She had had enough. She was going to get out of there tonight, and the flames in her dreams were going to help her dammit. She drifted off to sleep, preparing to see the flames that have taught her so much and hold them to their promise of helping her.

* * *

 _Familiar flames brought instant comfort to Rin, but she pushed past the warm feelings. She needed answers._

" _You've taught me a lot, but I need to know who you are. No more dancing around the subject. Just who are you?" Rin shouted into the black void beyond the flames._

" _Hasn't it been obvious, my child? I'm Satan, your father." came the calm reply._

 _Rin knew she should feel panic and disgust, but she couldn't bring herself to feel that way. Not after all that humans have put her through. Satan had shown her kindness when the Vatican showed her none. He gave her power when the Grigori sought to tear it away from her. She knew now that the world wasn't as black and white as she so naively thought when she was first introduced to the world of demons, and she knew that Satan had always looked out for her when no one else had. Not even her own brother had attempted to save her from the torture she'd endured._

" _I need to escape this place. I can't stand another day being the exorcists' plaything."_

" _I'm glad you feel that way. I just put everything in place to break you out of that hell," protective fire licked around her delicate form as he went on to explain the plan. Soon she'd be free of the wretched prison and would be able to take revenge upon so-called friends who stood by and allowed the torture to happen._


	4. Chapter 4: Escape

Hello everyone, thank you for the follows, favorites and reviews! It means so much to me that ya'll are still interested in this story even though I've done a poor job at updating. I'm hoping to get back into writing more chapters soon. Without further ado, here's the newest chapter of the story!

* * *

Rin awoke with a start. There was a ruckus outside her cell, one that she was surprised she had managed to sleep through up to that point. The guards were yelling, there were guns being fired, but most of all, Rin could hear the screaming of demons.

"Come on little sister, it's time to get you out of here," the white-haired demon said with a soft smile, approaching the bars of the prison.

"Who are you?" Rin asked.

"I'm hurt you don't recognize me from our earlier meeting. I'm Astaroth."

"Oh right. Satan said you were going to help get me out of here."

"Well come on, unless you'd rather stay here"

"No, I'm coming." Rin pulled her flames out, just like she had practiced in her dreams, and blue erupted forth. Concentrating, she made the metal bars of her cell door melt. She stepped through and Astaroth started to run, grabbing her hand.

Rin caught chaotic glimpses of the battlefield. Demons of all classes were battling the few exorcists stationed at the secret base to guard the princess of hell. They made their way outside and to a helicopter hovering just above the cement building, ladder trailing down. The way was kept clear of exorcists thanks to a handful of Naberiuses and Ghouls. They climbed up the ladder and the helicopter took off. _I'm safe_ , Rin thought with a sigh of relief.

* * *

Once the helicopter landed, Rin and Astaroth made their way out and into a complex that looked like a military base. Astaroth led Rin through what seemed like never ending tunnel after tunnel, twisting and turning every which way. The plain white walls did nothing to help Rin orient herself in the new environment. She felt safe and at home, and yet a remnant of her exorcist training had her feeling uneasy about being surrounded by so many demons. _But really, who are the true demons?_ She reminded herself, shuddering at the horrors she escaped from. It was finally hitting her that she was free. No more torture in the name of so called progress.

"We've arrived at Lucifer's chambers. Keep in mind he hasn't been in good health recently, so please be courteous to that fact and try not to tire him out too much," Astaroth warned Rin. She nodded in response and he turned to open the door.

"Lucifer, brother, I present to you our little sister Rin," Astaroth announced as the door swung open. A lush bed was the prominent feature of the otherwise plain room. Walls as white as the rest of the compound hosted a few pictures, most being whimsical paintings from eras gone by of gardens and mythical creatures. Surrounding the bed were red chairs as lush as the bed, in addition to an oxygen tank and a computer that monitored the vital signs of the lone occupant of the bed. His golden hair shone brightly in stark contrast to the pale sickly skin stretched over his thin and frail frame.

"Ah, Rin, my dear. I've been waiting to meet you. Father has told me quite a lot about you, but I shall like to get to know you myself. Do make yourself comfortable, this may be a long chat."

Rin settled into the chair next to the bed.

* * *

It had been a month since the mysterious attack on the research and development section of the Vatican. Yukio had heard whisperings of the rumors surrounding the attack, but no hard evidence of whatever the Vatican was determined to keep so under wraps. He sighed in frustration, there was something bugging him about the situation. Some gut feeling said to look into the incident, but the harder he pushed the more tight lipped his superiors got until they threatened to strip him of his rank for insubordination if he didn't stop.

"Mr. Okumura, is everything okay?" Bon asked, noticing the pained look on his teacher's face.

"Yes, everything is fine." He replied, shaking his head clear of those thoughts. He had to focus on the mission at hand. Along with himself and Shura, the rest of the exwires were on their way to Kyoto to stop the possible resurrection of the Impure King.

The train pulled up to the station and the group disembarked, heading to the childhood home of Bon, Konekomaru, and Shima. Once they had said their hellos and settled in, their mission would begin.


End file.
